Writing instrument



FIG. 1 is a perspective view of the invention;

FIG. 2 is a side view of the invention;

FIG. 3 is another side view of the invention, showing the side opposite that shown in FIG. 2;

FIG. 4 is a front view of the invention;

FIG. 5 is a back view of the invention;

FIG. 6 is a top view of the invention; and,

FIG. 7 is a bottom view of the invention. 

The ornamental design for a writing instrument, as shown and described. 